If you work with real-time data and need a way to process it efficiently, Pathway might be the tool for you. It is designed to help developers handle data streams and build applications that react to changes instantly. This guide will walk you through how to get started and show you how to use some of its key features.

Installing Pathway

Before anything else, you need to install Pathway. It requires Python 3.10 or later, so make sure you have the right version installed. Open your terminal and run:

pip install pathway

That is all you need to do to get Pathway set up on your system.

Understanding How Pathway Works

Pathway is built around the idea of processing data as it arrives. Instead of handling data in batches, it continuously updates results as new information comes in. Here are some of the main things you will work with:

  • Tables – These hold your data, similar to a spreadsheet or a pandas dataframe.
  • Input Sources – These bring data into your Pathway application, such as CSV files, databases, or API streams.
  • Transformations – These let you filter, sort, and modify data to match your needs.
  • Output Destinations – These allow you to save processed data in formats like JSON or send it to another system.

With these basic ideas in mind, let’s go ahead and build something.

Creating a Simple Pathway Application

Here is a small example that reads data from a CSV file, filters it, and writes the results to another file.

Step 1: Import Pathway

Start by creating a Python file and adding this line:

import pathway as pw

Step 2: Read Data

Use an input connector to load data from a CSV file:

table = pw.io.csv.read("input.csv")

Step 3: Process the Data

Let’s say you only want rows where the value in the "amount" column is greater than 100. You can do that with:

filtered_table = table.filter(table.amount > 100)

Step 4: Write the Output

Now, save the filtered data to a JSON Lines file:

pw.io.jsonlines.write(filtered_table, "output.jsonl")

Step 5: Run the Program

Save your file and run it using Python. Pathway will process the data and save the filtered results.

What’s Next?

This is just a simple example, but Pathway can do much more. It supports handling data from live streams, integrating with machine learning models, and managing complex transformations. If you want to explore more, check out these resources:

Once you get comfortable with the basics, you can start experimenting with real-time data processing and more advanced use cases. Pathway makes it easier to build applications that react to data changes instantly, and with a bit of practice, you will be able to create powerful solutions for your projects.